120 Questions
What type of wood components are made by bonding pieces of wood with glue or resin?
Engineered wood components
Which type of wood is typically used in construction?
Pine, Fir, Spruce
What is the main disadvantage of solid lumber according to the text?
Non-uniform dimensions
What is a significant factor affecting wood strength according to the text?
Weather conditions
What type of joint is formed by cutting complementary mating parts and securing them with glue?
Finger joint
Which engineered wood product is made from veneers that are not as uniform as those used in LVL?
Parallel Strand Lumber (PSL)
What is the main advantage of Thermoplastic Composite Lumber?
Resistance to weathering
Which type of wood panel product uses thin layers (veneers) glued together?
Plywood
What is the main distinguishing feature of OSB panels compared to waferboard?
Strength and stiffness due to strand orientation
Which wood panel product is primarily used for applications like sheathing, concrete formwork, and ship hulls?
Plywood
What is the main reason why Thermoplastic Composite Lumber is not intended for structural framing of buildings?
Lacks structural strength
Which wood product is characterized by being made from wood particles bonded with synthetic resins under heat and pressure?
Particleboard
What is the main difference between waferboard and OSB?
Waferboard has larger wafer-like pieces of wood while OSB uses smaller particles
What is the purpose of Composite panels in construction?
Serve several functions including insulation and structural support
What is the R-Value of a material with greater insulating effectiveness?
The R-Value increases
Which material is commonly used for firestopping to prevent the spread of fire?
Cement fiber board
What is the purpose of Exterior Insulation and Finish Systems (EIFS) in building construction?
Increase the insulative properties of a building
What is the purpose of brick or stone veneer on a wood-frame building?
To enhance the thermal insulating value of the wall
What classification is given to wood-frame buildings that have no interior finish materials?
Type V-B (wood frame)
What is pyrolysis in relation to wood?
The thermal decomposition of wood below 392°F (200°C)
What is the purpose of fire-retardant treatment on wood?
To reduce the rate of flame spread and increase ignition temperature
Why are void spaces considered a disadvantage in construction?
Void spaces increase the rate of flame spread through large volumes of air
In what type of construction are ignition-resistant features important?
Type V (wood frame)
In Balloon Frame Construction, what provides a channel for the rapid travel of fire between building levels?
Continuous studs
What advantage do the continuous studs in Balloon Frame Construction provide in minimizing over time lumber shrinkage?
Minimization of lumber shrinkage effects
Which type of construction is characterized by columns and beams with dimensions greater than those used in light-frame construction but smaller than those used in heavy timber framing?
Post and beam framing
What is a distinctive characteristic of Type IV (heavy timber) mill construction compared to Type III masonry construction according to the International Building Code?
Internal support column size
Which type of wood-frame construction involves creating square or rectangular shapes using posts and beams that require diagonal bracing or wall panels for additional support?
Post and beam framing
Why can the advantages of mill construction be reduced when a mill building undergoes a change of occupancy?
Creation of concealed spaces
What differentiates Type IV (heavy timber) mill construction from Type III (exterior protected) masonry construction according to the text?
Thicker dimensions of wood structural members and no combustible concealed spaces
What is a primary safety limitation of engineered wood systems highlighted in the text?
Early failure under fire conditions without a non-combustible covering
Which style of connector is most common in heavy timber trusses?
Through-bolts with steel gusset plates
What type of wood truss is used mainly for its appearance rather than structural reasons?
Heavy timber truss
What is a limitation of using screws or bolts to connect wood members as mentioned in the text?
Deformation of wood at the point of application
What can cause the thermal expansion of metal connectors in light wood frame construction according to the text?
Working loose from the wood members
Why are mortise and tenon joints rarely used in modern construction according to the text?
High cost and labor intensity
In light wood frame trusses, why do relatively slender wood members fail earlier in a fire according to the text?
"Swift collapse under fire conditions"
What is a major factor that contributes to structural collapse regardless of fire according to the text?
"High potential for sudden, catastrophic structural failure"
What is a significant disadvantage of using solid lumber in construction?
Non-uniform shrinkage and swelling
Which factor significantly affects the strength of wood components over time?
Moisture content
In what way does wood typically exhibit strength variations?
Varies based on species, grade, age, and growth rate
Why do engineered wood components offer advantages over solid lumber?
Strength and cost efficiency benefits
What is a distinguishing feature of glulam beams in heavy timber construction?
React similarly to solid timbers under fire conditions
What is a primary use of Laminated Veneer Lumber (LVL) in construction?
Manufacturing I-joists and thin beam sections
What is a distinctive feature of Oriented Strand Board (OSB) panels?
Long strand-like wood particles compressed and glued into layers
Why is Laminated Strand Lumber (LSL) typically used for short-span beams and columns?
It is made with long strands of wood up to 12 inches in length
What is the primary reason why Thermoplastic Composite Lumber is not intended for structural framing of buildings?
Its combustibility with a flame spread rating of 80
What makes Particleboard different from Waferboard?
Uses small wood chips and sawdust combined with resin
Why are nonveneered panels like Oriented Strand Board (OSB) stronger and stiffer than waferboard?
The strands are oriented in the same direction in each layer
What distinguishes Thermoplastic Composite Lumber from Plywood in terms of use?
Not intended for use in structural framing of buildings
What type of material is commonly used for firestopping to prevent the rapid spread of fire through concealed spaces within combustible construction?
Gypsum board
In construction, what is the primary purpose of Exterior Insulation and Finish Systems (EIFS)?
Increase the insulative properties of a building
Which material is NOT commonly used for siding in wood-frame buildings?
Concrete blocks
What is the main purpose of using solid-fill foam insulations in construction?
To reduce heat loss and noise
Which insulation material is treated with water-soluble salts to reduce combustibility?
Cellulose fiber
What is a distinctive feature of Structural Insulated Panels (SIPs) compared to traditional stud-based systems in construction?
Elimination of studs in favor of bonding panels directly together
What is the main advantage of balloon frame construction compared to platform frame construction?
Minimizing fire spread between building levels
Why does platform frame construction differ from balloon frame construction in terms of shrinkage resistance?
Use of more horizontal members
What is the purpose of ledger boards in balloon frame construction?
Securing joists for the second floor
In heavy timber construction, what is a characteristic feature that differentiates it from mill construction?
Use of masonry exterior
What distinguishes post and beam framing from heavy timber framing?
Structural member spacing
Why is mill construction considered an improvement over heavy timber design for fire resistance?
Elimination of void spaces
What is a common misconception about fire-retardant treated wood?
It increases the strength of wood after treatment.
Why is brick work in veneered walls difficult for a firefighter to assess?
It is challenging to visually determine if the brick work is aesthetic or structural.
How does the heat of combustion relate to wood as a building material?
The heat of combustion can be measured in Btu per pound or kJ/g.
What is a drawback of using surface coating as a fire-retardant treatment for wood?
Surface coating introduces volatile gases into the wood.
What can be inferred about engineered wood structures from the text?
Engineered wood structures can be built several stories high.
What do manufactured components used in building construction consist of?
Various materials like adhesives, dimensional lumber, metal fasteners, and panels.
What is a primary limitation of simply using screws or bolts to connect wood members?
Deformation of wood at the point of application
What is a common feature of connectors in light wood frame truss members?
Metal toothed plates driven into the wood members
Why are engineered wood products like I-joists becoming more common in construction?
They are economical, resource efficient, and custom-built with few limitations
What is a significant safety limitation highlighted for engineered wood systems?
Swift collapse under fire conditions
What is the main reason why mortise and tenon joints are rarely used in modern construction?
They have high labor intensity and cost
What is a characteristic that differentiates heavy timber trusses from light-frame trusses?
Members up to 8 or 10 inches versus 2-inch nominal members
What is a disadvantage of solid lumber, as mentioned in the text?
Predictable shrinkage and swelling
Which type of wood component is typically stronger parallel to the grain than against the grain?
Solid lumber
What is a key factor that affects the strength of wood components significantly over time?
Moisture content
What distinguishes Glulam beams from solid timbers under fire conditions?
No effect from heat exposure
What is a characteristic feature of Structural Composite Lumber (SCL) compared to traditional lumber?
Has comparable structural integrity under fire conditions
What distinguishes Parallel Strand Lumber (PSL) from other engineered wood products?
Greater uniformity in veneer thickness
What is the primary difference between Particleboard and Waferboard?
Particleboard is used for structural applications, while Waferboard is not.
What is the main function of Composite Panels in construction?
Enhance the insulation of buildings
Which material is commonly used for firestopping to prevent the spread of fire?
Cement fiber board
What is a distinguishing feature of Exterior Insulation and Finish Systems (EIFS) regarding their function?
They enhance the aesthetic appearance of buildings
Why are foam insulations treated with flame retardants in construction?
To prevent the spread of fire within walls
What is the main advantage of using Solid-fill foam insulations in construction compared to other types of insulation?
Enhanced resistance to environmental infiltrations
What building product was commonly used from the 1930s until the 1970s but is not used in the U.S. today due to causing respiratory ailments?
Asbestos
What aspect of brick or stone veneer can make it difficult for a firefighter to determine whether it is structural or aesthetic?
Thickness
In wood-frame buildings, what is the primary purpose of surface-to-mass ratio discussed in the text?
Affecting burning rate
What structural classification is given to wood-frame buildings that have no interior finish materials?
Type V-B
What is a characteristic feature of flame-retardant treated wood that distinguishes it from non-treated wood?
Improved fire endurance
What method of fire-retardant treatment for wood involves the reduction of volatile gases and slowing of flaming combustion?
Pressure impregnation
Why is platform framing more prone to shrinkage compared to balloon framing?
Platform framing uses fewer horizontal members than balloon framing
What is the advantage of the continuous studs in balloon framing?
Minimizes the effects of lumber shrinkage
How do the joists in balloon frame construction differ from those in platform frame construction?
Rest on vertical studs in platform framing
What is a distinguishing feature of heavy timber (mill) construction when compared to post and beam framing?
Includes trusses or beams for roof support
Why is mill construction considered an improvement on heavy timber construction?
Utilizes large-dimension timber and masonry exterior
What is a primary distinction between post and beam framing and heavy timber construction?
Size of the wooden columns and beams used
What distinguishes Laminated Strand Lumber (LSL) from Parallel Strand Lumber (PSL) in terms of use?
PSL is used for short-span beams, while LSL is used for long spans.
Which type of wood panel product is NOT intended to be used in the structural framing of a building?
Thermoplastic Composite Lumber
Why are Oriented Strand Board (OSB) panels stronger and stiffer than Particleboard?
Particleboard has wood particles oriented in the same direction in each layer.
What makes Waferboard different from Particleboard?
Waferboard uses thin sheets of wood glued together and then cut into squares or rectangles.
What is the primary advantage of using Plywood over Nonveneered Panels for sheathing?
None of these
What is a key difference between Type IV (heavy timber) mill construction and Type III (exterior protected) masonry construction?
Thicker dimensions of wood structural members
What is a primary reason for the resurgence of post and beam construction in rustic-style dwellings?
Economical and resource efficient
Which engineered wood product is becoming more common in construction due to its customizability and few application limitations?
I-joists
Why are mortise and tenon joints used only in rare cases in modern construction?
Artistic or quaint appearance desired
What is a characteristic feature of light-frame trusses commonly used for roof framing?
Small nominal members aligning in the same plane
In wood construction, what is a primary safety limitation of engineered wood systems?
Swift collapse under fire conditions
What is a significant factor affecting wood strength over time according to the text?
Thermal expansion of metal connectors
What is a common vulnerability of wood that makes it susceptible to deterioration?
Insect infestation
Why must firefighters approach wood-frame buildings showing exterior signs of deterioration with caution?
The building's susceptibility to decay
What type of construction has a lower potential for catastrophic failure according to the text?
Heavy timber construction
What forces can affect wood structures similar to buildings made from other materials?
Settling and erosion
What should firefighters maintain when approaching buildings showing exterior signs of deterioration?
Situational awareness
What makes wood uniquely vulnerable to deterioration according to the text?
Susceptibility to decay, insects, and shrinkage
What is a characteristic feature of heavy timber construction that makes it different from other building methods?
Lower potential for catastrophic failure
Why must firefighters approach wood-frame buildings showing exterior signs of deterioration with caution?
To maintain situational awareness of building conditions
What are wood structures subject to that can also affect buildings made from different materials?
Forces like settling, erosion, and weathering
What is a common indication of the deterioration of a wood-frame building according to the text?
Readily apparent signs from the outside
Study Notes
Codes and Standards
- Type IV (heavy timber) mill construction differs from Type III (exterior protected) masonry construction in terms of thicker wood structural members and no combustible concealed spaces
- Codes specify unique dimensions, attachment joints, and materials used in flooring and roofing surfaces for Type IV and Type III construction
Benefits of Using Wood in Construction
- Wood has an attractive, rustic finish when used on the surface
- Post and beam construction, which uses wood, is popular in rustic-style dwellings and small storage buildings
- Engineered wood products, such as I-joists, are economical, resource-efficient, and custom-built with few application limitations
- Wood I-beams are commonly used for floor joists and rafters in roof framing
- Heavy timber trusses are used for their appearance and are common in older timber construction
Types of Engineered Wood Beams
- Box beams and I-beams can be manufactured using plywood, laminated veneer lumber, or oriented strand board for the vertical webs and laminated veneer lumber or solid wood lumber for the flanges
- Manufactured I-joists are constructed of three engineered wood components bonded together to form an I-shaped cross-section
Connectors in Wood Construction
- Connectors between light wood frame truss members can include metal toothed plates driven into the wood members or nailed plywood gusset plates
- In heavy timber trusses, steel gusset plates with through-bolts are commonly used connectors
- Other styles of connectors include split-ring connectors, which provide a larger bearing surface for the transfer of load between two members
Considerations for Wood Construction
- Thermal expansion of metal connectors in light wood frame construction can cause the teeth to work loose from the wood, resulting in early failure
- A primary safety limitation of engineered wood systems is the possibility of swift collapse under fire conditions, especially if void spaces are not protected by a non-combustible covering or sprinkler system
- In modern construction, mortise and tenon joints are used only in rare cases where an artistic or quaint appearance is desired due to their high labor intensity and cost
Types of Wood Trusses
- Light-frame trusses have become popular for roof framing where the spans are small or moderate and use a series of 2-inch (50 mm) nominal members that align in the same plane
- Heavy timber trusses use members up to 8 or 10 inches (200 to 250 mm) and are used mainly for their appearance
- A split-ring truss uses a short circular piece of steel within and between two adjacent wood members to transfer load between the members
Connections in Wood Construction
- Using screws or bolts to connect wood members has a serious limitation: steel screws and bolts are stronger than wood, which can lead to deformation of the wood at the point of application and inefficient use of the wood
Structural Collapse of Wood Construction
- Structures with light and engineered materials have a high potential for sudden, catastrophic structural failure
Material Properties of Wood and Manufactured Components
- Wood is a unique building material that is cheap to produce and renewable
- Types of wood used in construction are typically softwoods, including pine, fir, and spruce
- Disadvantages of wood include non-uniform dimensions, weather conditions affecting size and shape, non-uniform shrinkage and swelling, intrinsic defects, and strength varying with species, grade, age, and growth rate
Solid Lumber
- Solid lumber includes dimensional lumber, boards, and timbers with standard measurements
- Nominal dimensions of lumber do not match actual dimensions due to finishing processes and shrinkage while drying
- Moisture content and load direction affect wood strength
Engineered Wood
- Engineered wood components are manufactured by bonding pieces of wood with glue or resin to form finished shapes
- Engineered wood components are rated according to the amount of weight they can carry once complete
Properties of Wood
- Wood is never dimensionally true
- Weather conditions can affect the size and shape of wood
- Wood does not shrink or swell uniformly
- Intrinsic defects include knots, knotholes, decay, insect damage, splits, and warping
- Wood strength varies significantly with species, grade, age, and growth rate of the tree
- Wood strength changes over time after components are placed in use
- Moisture content is a significant factor in wood strength
- Wood is stronger parallel to the grain than against the grain### Fire Resistance in Wood-Frame Buildings
- Wood-frame buildings are classified into several types based on their fire resistance:
- Type V-A (wood frame, protected): 1-hour fire-resistant structural framing
- Type V-B (wood frame): no fire-resistant structural framing
- Automatic sprinkler systems may eliminate the need for 1-hour structural fire resistance in some cases
Asbestos in Building Products
- Asbestos was commonly used in building products from the 1930s to the 1970s
- It can cause respiratory ailments and requires special handling and notification of environmental officials during overhaul
Brick or Stone Veneer
- A decorative layer of brick or stone over a wood-frame building
- Must be tied to the wood frame at 16-inch intervals
- Adds thermal insulation value to the wall
Combustion Properties of Wood
- Wood is combustible, with an ignition temperature of around 392°F (200°C)
- Factors affecting wood combustion include density, size, moisture content, heating rate, and air supply
- Pyrolysis is the thermal decomposition of wood, producing non-combustible gases initially, followed by combustible gases
Fire-Retardant Treatment of Wood
- Wood can be treated with fire-retardant chemicals to reduce its combustibility
- Fire-retardant treatment increases the ignition temperature of wood and reduces flame spread
- Two main methods of fire-retardant treatment: surface coating and pressure impregnation
Engineered Wood Products
- Made from wood particles bonded with glue or resin
- Engineered wood products provide strength and cost efficiency, but can fail unpredictably in fire conditions if unprotected
- Examples of engineered wood products: laminated wood, glued-laminated (glulam) beams, and structural composite lumber (SCL)
Heavy Timber Construction (Type IV)
- Characterized by heavy wooden structural members with a masonry exterior
- Heavy timber construction is more resistant to fire than light-wood framing
- Codes specify unique characteristics that differentiate Type IV construction from Type III (exterior protected) masonry construction### Structural Composite Lumber (SCL)
- SCL products are made from wood strands, strands, or veneers, combined with adhesives and pressed into large mats.
- Three types of SCL products:
- Parallel Strand Lumber (PSL): strongest of the three, used for heavily loaded columns and long spans.
- Laminated Strand Lumber (LSL): used for short-span beams and columns.
- Thermoplastic Composite Lumber: alternative to preservative-treated lumber, used for outside decks and railings.
Wood Panel Products
- Plywood: made from several thin veneer layers, rotary-sliced from rotating logs, and glued together.
- Standard sizes: 4 feet by 8 feet (1.2 m x 2.5 m).
- Applications: sheathing, concrete formwork, webs of composite beams, hulls of ships.
Nonveneered Panels
- Made from engineered wood formed into sheets using resin, heat, and/or pressure.
- Types of nonveneered panels:
- Oriented Strand Board (OSB): uses long, strand-like wood particles, stronger and stiffer than waferboard.
- Particleboard: made from small wood chips, sawmill shavings, and sawdust combined with a synthetic resin.
- Waferboard: made from thin sheets of wood veneer, glued together, and cut into squares or rectangles.
Definitions
- Thermoplastic: plastic that softens with an increase of temperature and hardens with a decrease of temperature.
- Polyvinyl Chloride (PVC): synthetic chemical used in the manufacture of plastics and single-ply membrane roofs.
- Nonveneered Panel: lightweight wood construction panel manufactured from wood chips, strands, wafers, or sawdust and a bonding agent.
Wooden Structural Panels
- Nonveneered panels:
- Made from engineered wood formed into sheets using resin, heat, and/or pressure.
- Types of nonveneered panels: OSB, Particleboard, Waferboard.
- Composite Panels:
- Serve several functions, including insulation and structural support.
- Consist of a face and back panel of plywood or OSB bonded to a central core material.
Insulation and Firestopping
- Insulation: used to prevent heat loss and reduce noise, measured by R-value.
- Firestopping: used to prevent the rapid spread of fire through concealed spaces, materials used include 2-inch lumber, gypsum board, and batts or blankets of mineral wool.
Exterior Wall Materials
- Siding materials: provide resistance to environmental and pest infiltration, chosen for functional or aesthetic reasons.
- Sheathing: provides structural stability, insulation, and an underlayer for the siding.
- Building wrap: acts as a vapor barrier, reduces infiltration of moisture and air.
Insulation Materials
- Noncombustible materials: glasswool, rockwool, fiberglass, and some older insulation materials that may contain asbestos.
- Loose-fill materials: granulated rock wool, mineral wool, glass wool, and cellulose fiber.
- Foam insulation: combustible, building codes impose strict regulations on its use.
Exterior Insulation and Finish Systems (EIFS)
- Exterior cladding or covering systems composed of an adhesively or mechanically fastened foam insulation board, reinforcing mesh, a base coat, and an outer finish coat.
- Also known as Synthetic Stucco.
Siding Materials
- Provide the exterior cladding of a wood-frame building, weather protection, and contribute to the appearance of a building.
- Combustibility of a siding material can affect fire behavior.
- Materials used for siding: aluminum, asphalt siding/shingles, cement board, plywood, stone, stucco, wood boards, wood shingles, vinyl.
Types of Structural Framing
- Balloon Frame Construction: exterior wall studs are continuous from the foundation to the roof, no fire stops between the studs.
- Platform Frame Construction: each floor is built as a separate platform, studs are not continuous beyond each floor.
- Heavy Timber Construction (Type IV): massive members used, characterized by heavy wooden structural interior supports with a masonry exterior.
- Post and Beam Framing: a form of wood-frame construction with columns (posts) and beams, using dimensions smaller than those used in heavy timber framing.
Explore the material properties of wood and manufactured components used in construction. Learn about different types of wood like Pine, Fir, and Spruce, as well as the disadvantages associated with using wood in building projects.
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